Experimental damage tolerance evaluation of thick fabric carbon/epoxy laminates under low-velocity and high-velocity impact and compression-after-impact

Impact experiments of thick fabric carbon/epoxy laminate specimens, with small thickness ratio, are conducted at distinct energy levels and thicknesses to characterise the damage process. These specimens loading conditions representative a new generation critical structural components in aviation, such as wing spars, landing gear beams fittings, that increasingly being made entirely from composites. The tests address need better understand process for ratio since existing experimental impact data large (thin laminates) may not be directly applicable. Two levels, two different layups methods (drop-weight gas-cannon) were used. Data high-speed cameras processed novel way, providing force during impact. C-scans micrographs used damage. results show 5 (20 mm thick) experience more bending compared 2.5 (40 thick). For gas-cannon impacts, this higher delaminated area. drop-weight impacts almost no differences size range analysed. influence layup on global response is negligible, but locally it can result significant variations dent depth. depth scales linearly area velocity. There clear correlation between compression-after-impact failure mechanisms residual strength. damage, current showed minimal reduction